Reusable recyclable thermoformed shipping containers

ABSTRACT

A thermoformed, reusable, recyclable shipping container comprising a thermoformed shell and a plurality of separate load bearing columns secured within said shell at various locations whereby the stacking load imposed on the containers will be at least partially borne by the load bearing columns.

CLAIM OF PRIORITY

This application claims priority to application Ser. No. 62/913,617,filed Oct. 10, 2019, and entitled REUSABLE RECYCLABLE THERMOFORMEDSHIPPING CONTAINERS.

FIELD OF THE INVENTION

Thermoformed plastic shipping containers, e.g. “dunnage” or trays.

BACKGROUND OF THE INVENTION

Thermoformed plastic shipping containers are typically a less expensivealternative to injection molded shipping containers or trays (see PriorArt FIG. 1). They are formed by heating a plastic sheet to a pliablecondition and forming it on a mold to give it its desired shape. (1PA)

Stacking is typically required of shipping containers (see Prior ArtFIGS. 2, 3). Injection molded containers become more competitive wherethe stacking loads imposed on the containers are higher. For loads of3,000 pounds or more, injection molded containers or trays are typicallyused because of their greater strength and stacked compressionresistance.

The stacking strength of the containers is obtained through theirgeometry and the thickness and strength of the plastic used tothermoform the walls. To facilitate stacking, stacking features arethermoformed into the containers, at thicknesses and shapes designed tobear the weight of the product loaded containers stacked on top of them.Heavier load requirements usually also result in increased wallthicknesses for the containers.

The stacking features of thermoformed containers typically include loadbearing support platforms 2 and non-linear walls 3 thermoformed into thecontainer, often formed in mirror image from one side of the containerto the other, such that successively stacked containers can be arrangedso that e non-linear walls cross each other in the stack (see Prior ArtFIGS. 1-3), The stacking features thermoformed into the containersrestrict the area available for product packing. In addition, the higherload requirements require thicker walls to increase wall strength. Bothof these requirements are drawbacks economically.

SUMMARY OF THE INVENTION

The present invention is a thermoformed, reusable, recyclable shippingcontainer comprising a thermoformed shell and a plurality of separateload bearing columns secured within said shell at various locationswhereby the stacking load imposed on the containers will be at leastpartially borne by the load bearing columns. As a result of thisinvention, the thermoformed shells themselves can be formed of thinnerplastic than containers having integrally formed stacking features.Further, the containers of the present invention can be madesufficiently strong so as to compete with injection molded shippingcontainers which are typically required for heavier load applications.The reduction or elimination of thermoformed stacking features means thecontainers have more storage space for products.

These and other objects, features and advantages of the invention willbe more fully understood with reference to the drawings, description ofthe preferred embodiments and claims of the specification.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a prior art thermoformed shippingcontainer;

FIG. 2 is a side elevation of a stack of the prior art containers ofFIG. 1 ;

FIG. 3A is an illustration of the way the walls of the prior artcontainers of FIGS. 1 and 2 stacked on top of one another;

FIG. 3B is a cross section taken as indicated in FIG. 3A;

FIG. 4 is a bottom perspective view of a preferred embodimentthermoformed shipping container of the present invention;

FIG. 5 is an upper perspective view of the preferred embodimentthermoformed shipping container;

FIG. 6 is a top perspective view of the preferred embodimentthermoformed shipping container;

FIG. 6A is a cross sectional view of a stack of two preferred embodimentcontainers;

FIG. 7 is a close-up perspective view of a supporting columnthermoformed into the preferred embodiment shipping container;

FIG. 8 is a close up of a preferred embodiment support column;

FIG. 9 is a close up of an alternative preferred embodiment supportcolumn projecting from the bottom of the container;

FIG. 10 is perspective view of a mold used to thermoform the preferredembodiment shipping container;

FIG. 11 is a close up of a support column receiver in the mold of FIG.10 ;

FIG. 12 is an upper perspective view of an alternative embodiment of thethermoformed shipping container of the present invention, in which theperimeter walls are formed with recessed portions to save material,without sacrificing strength; and

FIG. 13 is a front perspective view of two alternative embodimentcolumns, with one stacked on top of the other in a coupled manner.

DESCRIPTION OF THEE PREFERRED EMBODIMENTS Parts List

The numerical designations for the various parts discussed in thepreferred embodiment are as follows:

-   1 The preferred embodiment thermoformed, reusable, recyclable    shipping container-   10 thermoformed shell-   11 walls-   12 wall fusions-   13 ribs-   14 shorter ribs-   15 part-wells-   16 auxiliary wells-   20 load bearing columns-   21 retainer groove-   22 formed top well-   30 The thermoforming die for the preferred embodiment container-   31 spindles for supporting columns-   31 a holder well for holding columns-   32 mold walls over which shell walls are formed-   33 gaps between prongs and mold walls to facilitate fusion-   34 rib walls-   35 shorter rib walls-   36 wells for forming part holding wells-   40 Alternative embodiment column-   41 inner column wall-   42 inner column ribs-   50 Alternative embodiment column-   51 stem-   52 funnel shaped top-   53 insertion base-   53 a beveled edge on base 53-   100 Alternative embodiment shell-   111 short walls

In the preferred embodiment, the thermoformed, reusable, recyclableshipping container 1 comprises a thermoformed shell 10 and a pluralityof separate load bearing columns 20 secured within the interior of shell10 at various locations whereby the stacking load imposed on thecontainers will be at least partially borne by the load bearing columns(FIGS. 4-6 and 6A). This type of container is often referred to as a“tray.” To form container 1, the columns 20 are inserted over spindles31 and down into column holder wells 31 a in thermoplastic mold 30 (FIG.10 ), such that shell 10 is thermoformed around columns 20. As viewedfrom above (FIGS. 5, 6 ), columns 20 are sheathed in the thermoplasticmaterial of shell 10. As viewed from the bottom of shell 10 (FIG. 4 ;see also FIG. 9 , with an alternative column 40), the columns areunsheathed.

Preferably, columns 20 are located at least at the corners of container1. Additional support is provided by locating several columns 20 in theinterior of the space defined by the perimeter wells. Similarly,additional support is provided by locating columns 20 along the lengthof the perimeter walls between the corners thereof. Preferably, columns20 are located in and along the length of shell walls 11, or in ribs 13or 14, or at the junction thereof. Preferably, columns 20 are located incontainers 1 so as to bear most, more preferably substantially all, ormost preferably all of the stacking load placed on pallets 1. In thepreferred embodiment container 1 shown in the drawings, there arecolumns 20 at each of the four corners of the container, two more ineach of the four walls 11 of the container, and four located within theinterior space defined by the perimeter walls, at the junction ofinterior ribs 13 and 14.

Each column 20 is sufficiently long to extend to the top of the formedcontainer 1. By extending from bottom to top of container 1, columns 20serve as load bearing members on a container 1. One may also extend thelength of columns 20 to slightly above the level of the tops ofperimeter walls 11, and/or slightly below the level of the bottom ofperimeter walls 11.

Shell 10 is thermoformed over mold 30 with columns 20 inserted overspindles 31 and down into column holder wells 31 a located in the moldwhere the columns are to go (FIG. 10 ). Column holder wells 31 a are theprimary holder for the load bearing columns 20 during the moldingprocess. Each of the holder wells 31 a extends downwardly into mold 30sufficiently far that its bottom is located at what will be the bottomof container 1 formed on mold 30. In this way, columns 20 will rest onairy surface underlying a formed container 1. The thermoforming processused can be, without limitation, vacuum forming, pressure forming,compression forming and twin sheet forming, etc.

All of the spindles 31 project upwardly from the interior of a columnholder well 31 a in mold 30 (FIG. 11 ), Spindles 31 tend to stabilizecolumns 20 during the molding process. FIG. 11 shows such a spindle andcolumn holder well arrangement at a juncture of ribs 34 and 35. In thisway, columns 20 sit over spindles 31 and down into wells 31 a when themold 30 is set up for thermoforming.

As can be seen from FIG. 10 , there are 16 spindles 31 and holder wells31 a for 16 columns 20 (FIGS. 4-6 ), Shell 10 is thermoformed from aheated sheet of any of the generally used thermoplastics, e.g. ABS,HIPS, HDPE, PVC, PET and PETG. In the preferred embodiment, PE or HDPEis used. The thickness of thermoplastic sheet used depends on thedesired container strength and to some extent height of the container tobe formed. Thicknesses may range from 0.045 to 0.500 inches. Theresulting trays typically range from 1 inch to 30 inches in height.

Mold 30 includes a base 30 a, the spindles 31 and wells 31 a upon andinto which columns 20 are positioned for the thermoforming process, anda plurality of spaced perimeter mold walls 32, over which the walls 11of shell 10 are formed. Spindles 31 and column holder wells 31 a arelocated in the space between the ends of spaced mold walls 32, such thatcolumns 20 become part of shell walls 11 when shell 10 is thermoformed.The mold 30 also includes lateral mold ribs 34 which are shorter thanperimeter walls 32, over which ribs 13 of shell 10 are formed (compare10 to FIGS. 5, 6 ). Shorter longitudinal mold ribs 35 form shorter ribs14 in shell 10. Spindles 31 and column holder wells 31 a are placed atthe junction of mold ribs 34 and 35 such that columns 20 are reinforcedby shell ribs 13 and 14 when formed. Wells 36 in mold 30 form productcontaining wells 15 in shell 10. A pair of auxiliary mold wells 17 formauxiliary wells 16 in shell 10.

In addition, mold walls 31 are spaced apart lengthwise sufficiently farto create a gap 33 between the end of each mold wall 32 a column 20placed in each column holder well 31 a and over each spindle 31. Whilemold walls 31 form segments of wall 11 which a hollow between two facesformed on opposite sides of mold walls 32, gap 33 permits the oppositefaces of wall 11 to fuse together in gaps 33. These fused wall portions12 form on either side of a column 20 and further reinforce and stiffeneach column 20 (see FIGS. 5-7 ).

Columns 20 are made of a stiff rigid material. They can be metal,composite or made of any of the plastics normally used in thermoforming.Preferably, they are made of the same material as shell 10, such thatupon expiration of its useful life, each shipping and storage container1 can be reground as a unit, with it shell and columns still together,rather than having to separate the columns from the shells.

Columns 20 in the preferred embodiment are tubular in construction,though other shapes can be used. Preferably, columns 20 include aretainer feature, such as groove 21 near the top thereof (FIG. 8 ), suchthat plastic from the heated sheets during thermoforming tends to flowinto grooves 21 and help lock columns 20 in place in the formed shell10. The open top of each column causes a column top well 22 to form inthe top of each column when it becomes sheathed in the plastic of thethermoformed shell 10 formed over it.

When stacked (FIG. 6A), the columns 20 in each of the stacked containers1 line up with one another so that the weight of the successivelystacked trays 1 is at least partially borne by the columns 20, ratherthan by the shell walls or other shell parts. The tops and bottoms ofsuccessive columns 20 can be provided with interlocking features to helpkeep the columns 20 in alignment. To some extent, top wells 22 performthis function when engaged by the bottom of the column 20 above it.

The present invention makes it possible to design shipping containerswhich carry more parts than correspondingly dimensioned prior artcontainers. There are two reasons for this. First, there is no need tomold stacking features into the container as was required for prior artcontainers. The outside dimensions of prior art container 1PA and thepreferred embodiment container 1 are identical. Yet the preferredembodiment container 1 has eighteen product container wells vs. twelvefor the prior art container 1PA. A second reason more parts can becarried is that the compression strength of the preferred embodimentcontainer 1 is greater than that of prior art containers, since thecolumns bear most, if not substantially all of the stacking weight,rather than the container walls. More parts per container exert morecompression weight on the containers below. Finally, the presentinvention enables a thermoformed container to carry heavier parts.

COMPARATIVE EXAMPLE

In this comparative example, prior art container 1PA and preferredembodiment 1 were made to the same exterior directions for containingthe same parts. The packed weight of each prior art tray was 1990 poundsand, because the preferred embodiment tray held more parts, 2387 poundsfor preferred embodiment tray 1. The prior art tray was made of a sheetof 50-50 virgin-regrind HDPE, only the prior art tray was formed fromthicker material, 0.350 inch vs 0.200 inch for the preferred embodimenttray.

A stack of three half trays for each type was tested under compressionfor one hour. The protocol used to determine the compression load placedon each stack is based on the weight of four “packs.” A pack includesone pallet, 10 loaded trays, and 2 unloaded trays and a cover. Since wewere testing a stack of three half trays, the load used was half theweight of four “packs.”

For the prior art tray, this compression load was 3980 pounds. For thepreferred embodiment tray this load would have been 4774 pounds. That isgreater than the load for the prior art trays since each preferredembodiment tray holds eight more parts, each having a significantweight. However, for this comparison, we subjected the preferredembodiment stack of trays to an even greater weight, namely 5664 pounds.

The compression platen used is a “floating” platen, such that it seeksout the weakest point in the stack of trays. The results were measuredin the deflection in the height of the stack at its weakest point. Theresults obtained are as follows

Prior art Preferred Embodiment Sheet thickness .350 in. .200 in.Compression load 3980 lbs. 5664 lbs. Deflection 1.355 in. .318 in.

Thus thermoformed plastic trays made in accordance with this inventionwill support a significantly higher compression load, carry more partsper tray, and can be made of thinner plastic sheet material

ALTERNATIVE EMBODIMENTS

The column 40 used in FIG. 9 is an alternative embodiment. It is tubularlike column 20 but is stiffer in that it has an inner tubular wall 41connected to the interior face of the outer tubular wall by reinforcingwebs 42.

FIG. 12 shows an alternative embodiment container 1A. This design takesadvantage of the added strength provided by columns 20 by reducing theheight of exterior shell walls 111. This results in a cost savingwithout significantly sacrificing strength.

FIG. 13 is a front perspective view of two alternative embodimentcolumns 50, with one stacked on top of the other in a coupled manner.Each column 50 includes a stem 51, a funnel shaped top 52, and aninsertion base 53, which is narrower than stem 51 so that it can beinserted into the funnel 52 of a lower column 50 to facilitate ease oflocating and stacking of one column on top of another. A beveled edge 53a on the bottom of insertion base 53 facilitates the insertion process.

An alternative method of manufacturing the container would be to moldthe shell without placing columns in the mold. The shells would beformed separately with receiving sleeves into which the columns would beinserted and retained by press fit, adhesive or the like.

CONCLUSION

As a result of this invention, the thermoformed shells themselves can beformed of thinner plastic than containers having integrally formedstacking features. Further, the containers of the present invention canbe made sufficiently strong so as to compete with injection moldedshipping containers which are typically required for heavier loadapplications. The reduction or elimination of thermoformed stackingfeatures means the containers have more storage space for products.

Of course, it is understood that the forgoing are preferred embodimentsof the invention, and that various changes and modifications thereof canbe made without departing from the breadth and spirit of the invention.

The invention claimed is:
 1. A stackable container comprising: athermoformed shell having a bottom and perimeter walls; a plurality ofunconnected vertical columns located within the stackable container andthe perimeter walls, wherein at least some of said columns arepositioned adjacent to and within said perimeter walls; wherein saidthermoformed shell sheathes and secures said columns in position; andsaid columns are configured to at least partially bear a stacking loadimposed by a container positioned above the stackable container.
 2. Thecontainer of claim 1 comprising: said perimeter walls being hollow,having spaced side walls and a top wall, except adjacent said columnspositioned within said perimeter walls, where said spaced sidewalls arefused together.
 3. The container of claim 2 comprising: saidthermoformed shell being thermoformed of plastic; said columns eachhaving a retainer feature such that the plastic of said thermoformedshell tends to engage said retainer features when heated duringformation of said shell, thereby additionally securing said columnswithin said shell.
 4. The container of claim 3 comprising: saidthermoformed shell including interior upstanding ribs within the spacedefined by said perimeter walls least some of said columns projectingupwardly from said interior ribs.
 5. The container of claim 4comprising: each of said columns including a nesting feature at the topthereof, whereby when said container is stacked with others of saidcontainer, the bottoms of an upper container nest in said nestingfeatures of the tops of the container immediately below in such stack.6. The container of claim 5 comprising: said columns and saidthermoformed shell being made of the same plastic, whereby saidcontainer can be reground without having to first separate said columnsfrom said shell.
 7. The container of claim 1 comprising: at least someof said columns including a nesting feature at the top thereof, wherebywhen said container is stacked with others of said container, thebottoms of at least some of said columns in an upper container nest insaid nesting features in the tops of at least some of the columns in thecontainer immediately below in such stack.
 8. The container of claim 1comprising: said thermoformed shell being thermoformed of plastic; saidcolumns being made of plastic, which is the same plastic which saidthermoformed shell is made of, whereby said containers can be regroundwithout having to first separate said columns from said shell.
 9. Thecontainer of claim 1 comprising: said perimeter walls meeting oneanother at corners of said container; some of said columns being locatedat the corners of said perimeter walls.
 10. The container of claim 9comprising: several more of said columns being located along the lengthof said perimeter walls between said corners.
 11. The container of claim10 comprising: said thermoformed shell including interior upstandingribs within the space defined by said perimeter walls, some of saidcolumns projecting upwardly from said interior ribs.
 12. The containerof claim 1 in which said columns are located in said container so as tobear most of the stacking load placed on said container.